Solar Panels

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  • Blue Pacific Solar Products, Inc. BBB Business Review

 

Best Panels; Canadian Solar, SolarWorld, Panasonic HIT

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UL Listed Certified by CEC

Best solar panels from our comprehensive family of UL listed modules with 25 year manufactures warranty. Dramatically reduce your electricity costs. Say goodbye to ever-increasing energy rates. Government incentives can cut 30% or more off the complete installation cost. Visit our Grid-Tie Solar or Off-Grid Living page and do-it-yourself.

  • Solar Panels
  • Solar Cells & How Modules Are Made
  • Solar Panels by the Pallet
  • Resource Documents:

Mono VS Poly, What's the Difference? Which One is Best?

panel typeMulticrystalline solar cells are semiconductor photovoltaic (fancy word for solar) material composed of variously oriented, small, individual crystals sometimes referred to as polycrystalline or semi crystalline. Monocrystalline is a silicon wafer made from a single silicon crystal grown in the form of a cylindrical ingot. Monocrystalline, or single cell technology, is slightly more efficient than polycrystalline solar panels when tested in factory conditions. However, Mono panels cost more than Poly panels and the energy production difference is usually a fraction of a percent with all other things being equal. In a computer performance model comparison, the difference between the two types of panels on a 12 kW panel system over a years time with all other things being equal is nearly the same.

Why choose one over the other? Monocrystalline is usually the dark color solar panels with polycrystalline more of a blue hue. Both panel types are now manufactured with silver frames as well as black frames so select the panel that fits your power requirement, your homes aesthetics, budget and point of origin preference. trina

 

Solar Panel Decision Factors

panel typeThe price of solar panels are largely determined by the number of watts, the rated efficiency, the manufacturer and factors such as point of origin. Panel selection should be based on the installation application, durability and warranty and not on the price of the panel. All our solar panels are UL listed and have been certified by numerous independent testing laboratories with warranties ranging from 20 to 25 years. Anything less than 20 years should not be considered. Despite warranties, the life expectancy of most solar panels is 50 years or more. Solar works well in all climates and all elevations with panels installed in the 1960's that are still producing 70% of their original rated power output.

canadian solar

 

Canadian Solar Polycrystalline & Monocrystalline Panels

canadian solar

Canadian Solar panels ranked among the highest efficiency polycrystalline panels in the industry, bringing customer values of more energy production. Best Warranty Insurance, 25 year worldwide 100% warranty term coverage providing third party bankruptcy rights. Non-cancellable, by 3 top insurance companies. canadian25 Year Warranty, UL Listed.

Model / Part # Type Watts Pmax Amps Imp Volts Vmax Data Sheet WTY MIN Price Per Watt Price
*CS6K-275M
Mono Black Frame
1101030
Mono-Sipoly technology 275 8.80 31.3 canadian solar data 25 Yrs.canadian solar warranty 4 $0.84
Qty
*CS6K-280M-T4-4BB
Mono Black Frame
1101055
Mono-Sipoly technology 280 8.89 31.5 canadian solar 25 Yrs.canadian solar warranty 4 $0.84
Qty
*CS6X-325P
Poly Clear Frame
1101051
Poly-Sipoly technology 325 8.78 37.0 canadian solar 25 Yrs.canadian solar warranty 4 $0.78
Qty

canadian solar*Panels Ship in 3 to 5 Business Days After Funds Clear From California or New Jersey.

 

Even a small amount of shade is a bad thing.

tech notesWhen a solar panel is even slightly shaded, it is severely impacted. For example, with even 2% of a solar panel cell area is shaded, the power output of the panel is reduced by 33% a 17:1 impact factor! This is true even if a microinverter or power-optimizer is used. Look out for even small shade factors like overhead power lines or vent pipes in roofs. At Blue Pacific Solar® we want to help make sure you squeeze every watt of the sun's free energy you can from each PV module.

canadian solar

 

SolarWorld Monocrystalline Solar Panels

solarworld

SolarWorld is the largest U.S. solar panel manufacturer for more than 35 years. With roots in the United States back to 1975, SolarWorld continues to serve as a leading visionary for the modern solar industry. Creating and delivering clean, cost-effective solar power is SolarWorld's top priority. 25 Year Warranty, UL Listed.

Model / Part # Type Watts Pmax Amps Imp Volts Vmax Data Sheet WTY MIN Price Per Watt Price
Sunmodule Plus
SW 285 Mono
Black Frame /
SLW-1101027
USA Manufactured
Mono-Siwholesale solar 285 9.02 31.3 silicon 25 Yrs.cells 4 $0.98
Qty
Sunmodule Plus SW
295 Mono
33mm Clear Frame /
SLW-1101045
USA Manufactured
Mono-Siwholesale solar 295 9.45 31.5 silicon 25 Yrs.cells 4 $0.97
Qty
Sunmodule Plus SW
300 Mono
Clear Frame /
1101011
USA Manufactured
Mono-Siwholesale solar 300 9.57 38.2 silicon 25 Yrs.cells 4 $0.97
Qty
Sunmodule XL
340 Mono
Clear Frame /
1101015
DE Manufactured
Mono-Siwholesale solar 340 9.1 38.0 silicon 25 Yrs.cells 4 $0.97
Qty
Sunmodule XL
345 Mono
Clear Frame /
SLW-1101042
DE Manufactured
Mono-Siwholesale solar 345 9.1 38.2 silicon 25 Yrs.cells 4 $0.99
Out of Stock
Qty

solarworldSolarWorld Panels Ship in 3 to 5 Business Days After Funds Clear.

 

ac power

Myth Vs. Fact. Solar Does Not Work On Cloudy Days.

Myth - Solar creates electricity from visible light. Did you ever get sunburn on a cloudy day? Cloud cover reduces the power of a module by a third or less than it's sunny day output. Even in the fog in San Francisco, solar panels will produce up to 70% of their rated power. Solar performs well in all climates, latitudes and altitudes. IE: Germany has installed about 40% of the worlds solar power accounting for about 7% of the countries electricity generation but only has about the same amount of average sun (Solar Irradiance) as Fairbanks Alaska.

qcells

 

QCELLS Solar Polycrystalline Panels

hanwah solar

QCells is a flagship company of Hanwha Group, a FORTUNE® Global 500 firm and a Top-Ten business enterprise in South Korea. It is headquartered in Seoul, South Korea, (Global Executive Headquarters) and Thalheim, Germany (Technology & Innovation Headquarters) and is the world’s largest solar cell manufacturer as wells as one of the largest photovoltaic module manufacturers.   25 Year Warranty, UL Listed.

Model / Part # Type Watts Pmax Amps Imp Volts Vmax Data Sheet WTY MIN Price Per Watt Price
QPRO BFR G4.3 265W
Black Frame
1101039
Poly-Simulticrystalline 265 8.62 30.75 qcells data 25 Yrs.qcell warranty 4 $.74
Qty
Q.PLUS BFR-G4.1 275W
Black Frame
1101004
Poly-Simulticrystalline 275 8.77 36.13 qcells data 25 Yrs.qcell warranty 4 $.74
Qty
Q.PLUS L-G4.2 325
Clear Frame
1101041
Poly-Simulticrystalline 325 8.85 36.7 qcells data 25 Yrs.qcell warranty 4 $.75
Qty

trina solarQCELLS Solar Panels Ship in 3 to 5 Business Days After Funds Clear From California, New Jersey.

trina solar

 

Trina Solar Monocrystalline Panels

trina solar

Trina Solar Limited is a leading manufacturer of high quality PV modules with a solid reputation as a solar pioneer. Growing to 14,200 employees worldwide since it was founded in 1997, Trina Solar is known globally as a manufacturing powerhouse. Trina Solar has shipped 11GW since 2007 and has emerged as the #1 PV manufacturer in the world with 3.66GW shipped in 2014. With $2.3B in revenues, Trina Solar is a strong player that has thetrina resources and reputation to back it's warranty. Photovoltaic projects rely on high quality products that stand the test of time for project inputs ranging from engineering design to project financing and more.   25 Year Warranty, UL Listed.

Model / Part # Type Watts Pmax Amps Imp Volts Vmax Data Sheet WTY MIN Price Per Watt Price
TSM-280DD05A.05(II)
Mono Black Frame
1101047
Mono-Simulticrystalline 280 8.84 31.7 trina solar data 25 Yrs.trina solar warranty 4 $.65
Qty

trina solarTrina Solar Panels Ship in 3 to 5 Business Days After Funds Clear.

lg

 

Panasonic Monocrystalline 19.7% High Efficiency Solar Panels

lg panels

Panasonic a leader in consumer electronics, business solutions and industrial components has been in the solar business for 40 years, providing high efficiency and high quality solar panels HIT® for over 17 years. 25 Year Warranty, UL Listed. panasonic

Panasonic HIT® solar panels are highly efficient and produce more power per square feet than traditional products. While the flat surface of other panel reflects sunlight, Panasonic’s unique pyramid structure helps the cell surface absorb more sunlight which generates more energy.

Model / Part # Type Watts Pmax Amps Imp Volts Vmax Data Sheet WTY MIN Price Per Watt Price
Panasonic 325W Mono
Black Frame /
VBHN325SA16
1101032
Mono-SiLG 325 5.65 57.6 LG 25 Yrs.LG 4 $1.25
Qty

lg solar*Panasonic Panels Ship in 3 to 5 Business Days After Funds Clear.

 

What happens when you mix different watt (sizes) & brands of solar panels?

panel typeIn most situations mixing dissimilar panels in the same solar array is not ideal, but also not a problem. Here is what happens. When paralleling panels of different current (amps) ratings, the output of the array will simply be the sum of the combined voltages. The lower voltage units will begin to taper off sooner as high battery voltage is reached. If the solar panels are used for direct power, the array voltage will be the approximate average module voltage. When series connecting strings of dissimilar panels, the current (amps) will be approximately that of the weakest panel in the string.

lg

 

LG Monocrystalline 19.2% High Efficiency Solar Panels

lg panels

With more than 50 years of experience as a global pioneer in electronics technology, LG Electronics stands ready to harness the power of the sun for you. Backed by 25 years of intense research and development far surpassing industry standards, LG Solar's Korean made solar panels are uniquely designed to offer the superior quality, field tested performance, lgdurability and reliability customers the world over have come to expect from LG. 25 Year Warranty, UL Listed.

High efficiency LG NeON™ 2 Module Cells: 6 x 10 Module efficiency 19.2% high power output.The rear of the cell used in LG NeON™2 will contribute to generation, just like the front; the light beam reflected from the rear of the module is reabsorbed to generate a great amount of additional power.

Model / Part # Type Watts Pmax Amps Imp Volts Vmax Data Sheet WTY MIN Price Per Watt Price
LG, LG315N1C-G4 Mono
Black Frame /
KS504900
Mono-SiLG 315 8.08 30.4 LG 25 Yrs.LG 4 $1.15
Qty

lg solar*LG Panels Ship in 3 to 5 Business Days After Funds Clear. Continental United States Shipments Only.

 

Myth Vs. Fact. Panels Made in China are Inferior to Other Panels

ac power

Myth - Most of the concerns over quality centers on panels made in China. There is some truth behind these stories but like all news stories there is a grain of truth that only makes an interesting story if the exceptions are played up. Most solar modules are fine. Of course, companies that are losing millions per quarter are looking for ways to cut corners. Most of those companies are on their way to oblivion and Blue Pacific Solar® chooses not to do business with those companies. We do not sell "Type B" or blemished panels either. All the panel manufactures you will find on this page have passed our entrance gate criteria which is: the panels we sell must be UL listed, must be certified by the California Energy Commission which does independent testing, must have a 25 year guarantee, must have US representation and we cannot find out anything bad about the module manufactures products or their company.

 

power definitions • Pmax = Maximum rated power at *STC
• Voc = This value is the unloaded output voltage of the panel
• Vmp = Maximum or peak power voltage is the maximum power produced under *STC conditions. (Sometimes Vpp on panel data sheets.)
• Isc = Is the current (AMPS) produced by the solar panel at STC (Standard Test Conditions) when output voltage is -0- Volts.
• Imp = Maximum power current is when the peak power is produced at STC conditions. (Sometimes called Ipp on panel data sheets.)

 

Panel Performance, *STC VS PTC; Real World

panel typeTip: *STC - To learn more about solar panels and how they are measured you need to know what STC stands for. STC in an acronym for "Standard Test Conditions". All solar panels are rated in Watts. The watt rating is how much power (amps times volts) the panel will produce in full sunlight at 25 degrees C (77F). This is the industry standard (STC) for all PV panel ratings (PV means Photovoltaics which is a fancy word for solar). Solar panel manufactures have long used this test standard which is 1,000 watts per square meter solar irradiance, 1.5 Air Mass and a 25 degrees C. cell temperature.

PTC is an acronym for "PV-USA". The PV-USA test conditions were developed at the PV USA test site at the University of Davis, California for standards established by the California Energy Commission that are considered closer to real world conditions (Real World Vs. STC factory test conditions). The PTC rating test is 1,000 watts per square meter solar irradiance, 1.5 Air Mass, and 20 degrees C. ambient temperature at 10 meters above ground level and wind speed of 1 meter per second. In California, solar panels manufactures must be tested and rated independently at the PV USA test facility at the University of Davis (CA) to be considered for rebates.

The ambient temperature rating (PTC) is generally considered a better real world standard than factory conditions because silicon solar cells average about 20 degrees C. above ambient temperature in the real world, cell voltage drops as temperature increases. A module's power output in real life conditions is lower than the power measured at the panel manufacturing factory where cell temperature is maintained at a controlled 77 degrees F. (25 C).

STC Vs. PTC Cell voltage drops about 0.08 volts per degree C. in environments which exceed 25 degrees C. That means an STC rating of 17 volts can actually become a PTC (PV-USA) rating of 15 or 16 volts. Using Ohm's Law, volts times amps is equal to watts which equals power, so a reduced voltage, means reduced watts.

Neither PTC nor STC account for all "real-world" losses. Actual solar systems will produce lower outputs due to soiling, shading, module mismatch, wire losses, inverter and transformer losses, shortfalls in actual nameplate ratings, panel degradation over time, and high-temperature losses for arrays mounted close to or integrated within a roofline.

Panel Performance, How Irradiance (Amount of Sun) and Temperature Affect Real World Output

i-v curve

panel typeTip: As we mentioned above, solar systems rarely operate at STC performance levels. An "I-V" curve is a graphic representation of all possible voltage and current (amps) operating points for a solar panel in different conditions. I-V curves of panels depend upon temperatures and the amount of sun so modules are usually only partially loaded throughout the day. From sunrise to sunset the amount of sun on the panels varies more than the temperature. The changes in irradiance (fancy word for sun in a given area) affect the panel current most of all since the current is directly dependent on the amount of sun hitting the panel. When the irradiance drops by 1/2, the amount of electricity generated by the panel drops by 1/2. By contrast, the maximum power point (MPP) voltage stays relatively consistence with the changing sun light. The example is based on a 150 watt 4 volt module but most solar systems are connected in series so the changes in MPP voltage can add up to much more than what is shown in the example.

Additionally, temperature affects the solar panel voltage much more than current. When we design an off-grid battery based solar system, we look at the location and the voltage of the battery bank to make sure at a minimum, the system will produce 20% more voltage than the battery bank requires to recharge on hot days where the system will be located. In the wintertime amp (current) output rises dramatically in cold weather. Panels work better in the cold than in the heat given the same solar irradiance. It is common for a panel to outperform it's STC rating during extremely cold days so the charge controller (off-grid systems) and inverter (grid-tied systems) that is selected needs to be rated for the climate in which it is going to be installed.

Solar Cells

Photovoltaic (PV) cells help capture energy from the sun and transform it into electricity. Solar energy is a non-polluting, renewable resource. Unlike fossil fuel-dependent power plants, it does not have carbon byproducts or contribute to climate change. It is also free and available to everyone. For these reasons, solar power is a great energy choice for eco-conscious individuals and communities. Sunlight can be used to power homes, businesses and industry through solar arrays.

PV cells, also called solar cells, work by absorbing photons in sunlight. The photons then pass through positive and negative-type layers of a semiconductor where their electrons create an electrical field. In many cases, the electrical energy is sent from the semiconductor to a battery to complete the circuit. The energy is stored in the battery for later use.

Many solar cells use silicon semiconductors. Silicon is an abundant resource that, when properly purified and implemented, can efficiently help create electricity. The element is used in photovoltaics in single crystalline, multicrystalline and amorphous forms. Take a look at the properties that make these semiconductors unique.

Single Crystalline Single crystalline silicon semiconductors are very efficient and very expensive to create. They are, historically, the most popular type of semiconductor. In single-crystal silicon, one crystal grows the entire framework of the material. This is usually done by melting the silicon in an oven, where it forms a cylinder. Because of its simple foundation, the silicon's atoms are arranged in a very orderly and uniform fashion. This makes it highly efficient.

The silicon cylinder is then cut into wafers. It is next doped with other material to create its positive and negative layers. The doped silicon wafers are then assembled to create PV cells. Because the assembly technology has been established and tested over time, it is now an efficient manufacturing process.

Multicrystalline (Polycrystalline)

Multicrystalline silicon semiconductors are slightly less efficient and less expensive to create than their single-crystalline alternatives. Multicrystalline semiconductors are commonly created by pouring lower-grade molten silicon into molds. The silicon cools in a block and then is sliced into square-shaped wafers. Grainy crystals in this type of silicon hamper electron flow and create inefficiencies. This reduces power outputs. The wafers are then doped with other elements so that it has n- and p-type layers. The finished cells are then placed into PV modules.

Amorphous (Thin Film)

Amorphous silicon semiconductors do not have crystal structures. Their atoms are disorganized. The silicon contains many structural barriers and dangling bonds that cause it to be an inefficient semiconductor. Manufacturing amorphous PV cells is cheap, though. This makes it a popular cell type for solar gadgets that do not need a lot of power to run. To create an amorphous semiconductor, silicon vapor is spread in a thin film onto glass or steel. While the PV cell is great at absorbing sunlight, the material tends to be unstable when initially exposed to the sun. Overall power output may decrease for a period of time after first use. This makes it unpopular for many large-scale consumer applications.

solarworld how solar made

 

Trina Solar Pallet Quantity Price Polycrystalline Panels

trina solar

Founded in 1997 with over 20 offices worldwide and 13,700 employees, Trina solar panels are UL certified and approved by the California Energy Commission. Trina Solar was named by EuPD Research as the "Top Brand PV" in Germany in 2013. Photovoltaic projects rely on high quality products that stand the test of time for project inputs ranging from engineering design to project financing and more. Relative to industry peers, Trina products have a strong track record of reliability and performance in the field. As a vertically integrated company, Trina tightly controls quality at every step from silicon crystallization to module deployment in the field with 30 in-house quality tests. Trina quality is guaranteed by a 25-year industry leading warranty. 25 Year Warranty, UL Listed.

Model / Part # Type Watts Pmax Amps Imp Volts Vmax Data Sheet WTY MIN Price Per Watt Price
*TSM-260PD05.08
Black Frame
1100954P
Poly-Simulticrystalline 260 8.50 30.6 trina solar data 25 Yrs.trina solar warranty 30 Out of Stock
$0.88
Qty

trina solarTrina Solar Panels Ship in 3 to 5 Business Days After Funds Clear From California, New Jersey or Hawaii. The 305W TSM-305PD14 are not available at this time in HI.

Best Wholesale Solar Panels Prices efficient quality high-performance PV modules

Best solar panels are the only panels Blue Pacific Solar® sell and we offer these at wholesale prices. Homeowners everywhere are buying solar panels that they can DIY (Do-it-yourself). Polycrystalline and monocrystalline solar panels from Blue Pacific Solar are priced to make our modules affordable for all residential and business roof and ground mount applications.

Solar Panels: Harvesting the Sun's Free Energy

Harnessing the power of the sun seems both ancient and incredibly futuristic. Any given day, the earth receives 6,000 more times the solar energy it needs to power its current needs. The life-sustaining power of the sun that was worshipped in antiquity has become the energizing force of today powering homes and eventually even the cities of tomorrow. While people have been benefiting from and learning about solar energy for untold centuries, the actual solar revolution we are experiencing today began in the twentieth century with the production of the first practical photovoltaic (PV) cell in 1954. Since then, the power of the solar panel and its eventual commercialization is one of the driving forces of the alternative energy future the world is working toward today.

History of Solar Technology

The solar or photovoltaic (PV) cell is essentially the building block of the solar panel. In 1839 at the age of nineteen, A.E. Becquerel made the first solar cell in France. Regarded as a marvel, this early solar cell wasn’t improved upon until 1883 when selenium was used as the cell’s semiconductor. It wasn’t until 1905, however, that the photovoltaic effect was thoroughly explained by the likes of Albert Einstein who wound up winning the Nobel Prize as a result of his explanations in 1921. Of course, the practical solar cell didn’t come about until 1954 when Bell Laboratories created a silicon-based cell that demonstrated a 6% efficiency rate (the earlier cell only demonstrated .5% efficiency). By 1960, the solar cell’s efficiency hit 14%. The 1960s and 70s would see a demonstrable increase in scientists working to make solar commercially viable from a price per watt standpoint. It wasn’t until the American energy crisis of the 1970s, though, that solar really hit its stride and improvements in the technology would finally launch solar as a viable commercial option for electricity in the 1980s.

Solar in Recent Decades

From the 1980s on, solar use and solar advances have increased steadily, albeit with occasional dips, in both North America as well as other parts of the world. Today, Germany leads the solar initiative with more solar production and penetration than anywhere else in the world. Advances in solar cells and solar panels are now beginning to challenge traditional fossil fuels in terms of both efficiency and cost. Yet solar is clean energy and its sustainable renewal has more and more people around the globe energizing their homes with the power of the sun. In the remote villages of many developing nations where electricity has never been used, people are skipping fossil fuels altogether and going straight to alternative and eco-friendly energies like solar.

Some Interesting Fun Facts about Solar Energy

  • Though not the largest user of solar energy, China is the world’s leading producer of solar cells.
  • Currently, Germany is producing so much excess alternative green energy using solar that it is now selling this power to neighboring nations.
  • A ton of sand used to make photovoltaic cells produces the equivalent amount of energy as 500,000 tons of coal burned up in a power plant.
  • A plane fueled by solar energy crossed the United States in 1990 exciting the world with the real possibility of moving beyond reliance on oil and other fossil fuels.
  • While a mere few decades ago most U.S. residents could not afford to install solar power systems in their homes, today with wholesale prices of the best solar panels, costs represent a 400% decrease from costs three decades ago.

To better understand the cost of the different types of solar panels and what makes one cheaper and one more expensive, we need to look at the two most common module materials. Monocrystalline silicon solar panels are made from a ingot of highly pure poly silicon melted and mixed with boron. The monocrystalline silicon seed is dipped into a molten bath over many hours until it grows into a large cylindrical crystal. Monocrystalline solar used most commonly on homes and businesses have an efficiency of 14% to 17%.

Canadian Solar, SolarWorld, and Trina polycrystalline silicon modules are made from a cast of many silicon crystals because it makes for modules that have different performance characteristics than monocrystalline solar panels. You can usually tell the difference between the most efficient solar panels which are monocrystalline and the cost of polycrystalline solar panel not just because of cost, but polycrystalline solar panels generally have a blue hue Vs. the black color monocrystalline solar panel.

At Blue Pacific Solar a question our consultants are asked often is what is the most efficient solar panels? Efficient solar panels are calculated on the ratio of power output to power input. What that means in laymen's terms is solar irradiance (the suns energy) is multiplied by the area of the solar device to determine the watts of solar power. (Electrical Power) The more of the suns energy (solar power per sq. meter) that is converted to electricity as a relationship to the size of the solar module, hence, the higher the efficient solar panel. The real answer to the question depends on the usage. As an example, thin film solar is not as efficient as monocrystalline or polycrystalline solar panels, but does better in extremely hot environments.

Solar panels are formed from many solar cells wired together to form a solar panel or module. Solar panels are constructed from solar cells that are sandwiched between several layers of protective materials, supported by an aluminum frame with some type of glass cover. Where you start to really see the difference between cheaply constructed and best quality solar panels is in the assembly, materials used in the panel parts and how many blocking diodes a panel may have. Higher quality solar panels have more blocking diodes (which improve performance is slight shading issues exist) and use higher quality low iron glass and durable frame materials.

Bypass or blocking diodes are used to pass current around rather than through a group of solar cells. The electrical current is allowed to pass around a cell or group of cells that have been shaded or develop an open-circuit condition. This process many times distinguish the difference between cheap PV modules and best solar panels where higher quality standards are adhered to. Trina Solar, Solarworld and Suniva solar panel manufactures set a high bar for all other residential solar panel companies. You can buy cheap solar panels, but be careful you are getting a quality product not a defective or flawed rejected panel which sometimes are sold as type A panels without blemishes.

Blue Pacific Solar® wholesale to the general public SolarWorld, and Canadian Solar have been extensively tested not only by the factory under standard and uniform test conditions (STC), but also they must be independently tested and listed with the California Energy Commission. We are distributing modules direct to homeowners that are only UL listed with a minimum 20 year guarantee from a manufacture that has been in business more than 5 years. Best solar panels for your home, quality wholesale prices; volume purchased from well established PV module manufactures.